• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1994.05a
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• pp.1-4
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• 1994

In this study. the microwave dielectric properties, such at dielectric constant(${\varepsilon}_{\gamma}$), unloaded quality factor multiplied with resonant frequency($Q_{u}$.f), and temperature coefficient of resonant frequency(${\tau}_{f}$), were investigated for the low-temperature sintered (Pb, Ca)$ZrO_3$ with $V_2O_{5}$ additives as well as structural properties. As a result, (Pb,Ca)ZrO$_3$ with 0.2 wt% $V_2O_{5}$ additive, sintered at $1200^{\circ}C$, showed good properties like ${\varepsilon}_{\gamma}$ 109, $Q_{u}$.f 2736 GHz, and ${\tau}_{f}$ -2.94 ppm/$^{\circ}C$. Especially ${\tau}_{f}$ was much better than ($Pb_{0.63}Ca_{0.37}$)$ZrO_3$ of which ${\tau}_{f}$ was known to be + 13.4 ppm/$^{\circ}C$, so it seems to be applicated in micorowave device components.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.11a
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• pp.248-251
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• 1999

The microwave dielectric properties of The Dielectric Properties of $Ba_{1-x}$A$_{x}$(Mg$_{1}$3/Nb$_{2}$3/)O$_3$ (A = Sr, Ca, x = 0, 0.2 ,0.4 ,0.6, 0.8, 1.0) were investigated. In composition of $Ba_{1-x}$A$_{x}$(Mg$_{1}$3/Nb$_{2}$3/)O, densities are decreased with increasing x values. Grain sizes are decreased with Sr content and Increased with Ca content. The hexagonally ordered superstructure was observed in $Ba_{1-x}$Sr$_{x}$(Mg$_{1}$3/Nb$_{2}$3/)O$_3$(BSMN) systems, the intensity of superlattice increased with x value. In $Ba_{1-x}$Cr$_{x}$(Mg$_{1}$3/Nb$_{2}$3/)O$_3$(BSMN) systems, the additional diffraction patterns were shown. The highest value of $\varepsilon$$_{r}$ was shown in x=0.2 of BCMN systems and the value was 41.9. The highest Q$\times$f was shown in x=0.2 of BSMN systems and the value was 68,000. $\tau$$_{f}$ were shown 0 ppm/$^{\circ}C$ near x=0.8.TEX> near x=0.8.0.8.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.5
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• pp.613-623
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• 2012

In this paper, we present an ultra miniaturized voltage tuned oscillator, with HMIC-type amplifier and phase shifter, using LTCC artificial dielectric resonator. ADR which consists of periodic conductor patterns and stacked layers has a smaller size than a dielectric resonator. The design specification of ADR is obtained from the design goal of oscillator. The structure of the ADR with a stacked circular disk type is chosen. The resonance characteristic, physical dimension and stack number are analyzed. For miniaturization of ADRO, the ADR is internally implemented at the upper part of the LTCC substrate and the other circuits, which are amplifier and phase shifter are integrated at the bottom side respectively. The fabricated ADRO has ultra small size of $13{\times}13{\times}3mm^3$ and is a SMT type. The designed ADRO satisfies the open-loop oscillation condition at the design frequency. As a results, the oscillation frequency range is 2.025~2.108 GHz at a tuning voltage of 0~5 V. The phase noise is $-109{\pm}4$ dBc/Hz at 100 kHz offset frequency and the power is $6.8{\pm}0.2$ dBm. The power frequency tuning normalized figure of merit is -30.88 dB.

• Proceedings of the KIEE Conference
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• 2004.07c
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• pp.1615-1617
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• 2004

5 mol% $BaWO_4$를 첨가시켜 합성한 Ba$(Mg_{1/3}Ta_{2/3})O_3$를 이용하여 비방사유전세선로에 삽입되는 세라믹스 공진기를 제자하고 기존의 $MgTiO_3-CaTiO_3$계 세라믹스 공진기와 공진특성을 비교하여 그 특성을 고찰하였다. 그 결과 BMT 세라믹스는 기존의 $MgTiO_3-CaTiO_3$계 세라믹스보다 품질계수가 2배 이상 크게 높게 측정되었고, 측정 사진의 관찰 결과 전파차단성도 우수할 것으로 예상되기 때문에 BMT가 비방사유 전체선로에 삽입되는 유전체 공진기 재료로서 적용될 경우 우수한 공진특성을 발휘할 것으로 판단된다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.11a
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• pp.27-28
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• 2009

In this study, we have fabricated the 3 wt% $Li_2CO3$ doped $(Ba,Sr)TiO_3$ thick films on the Ag/Pd printed $Al_2O_3$ substrates for the LTCCs (Low Temperature Co-fired Ceramics) applications. From the X-ray diffraion analysis, 3 wt% $Li_2CO3$ doped BST thick films on the Ag/Pd printed $Al_2O_3$ substrates, which sintered at 900 $^{\circ}C$ have perovskite structure without any pyro phase. The dielectric properties of 3 wt% $Li_2CO3$ doped BST thick films were measured from 1 kHz to 1 MHz. To investigate the electrical properties of 3 wt% $Li_2CO3$ doped BST thick films, we employed the impedance spectroscopy. The complex impedance of 3 wt% $Li_2CO3$ doped BST thick films were measured from 20 Hz to 1 MHz at the various temperatures.

• Transactions on Electrical and Electronic Materials
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• v.10 no.4
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• pp.125-130
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• 2009

The clamping voltage characteristics and accelerated aging behavior of CoCrTb-doped Zn/Pr-based varistors were investigated for different sintering temperatures. The best clamping voltage characteristics were obtained for the varistors sintered at $1330^{\circ}C$, with a clamping voltage ratio (K) of 1.63 at a surge current of 5 A and 1.75 at a surge current of 10 A. The varistors sintered at $1330^{\circ}C$ exhibited the highest stability, with -0.1% in $%{\Delta}E_{1\;mA}$, -0.2% in $%{\Delta}{\alpha}$, and +15.5% in $%{\Delta}J_L$ for E-J characteristics under a stress state of 0.90 $E_{1\;mA/120^{\circ}C$ /24 h. Furthermore, it exhibited $%{\Delta}{\varepsilon}_{APP}$' of -0.7% and $%{\Delta}tan{\delta}$ of +5.7% for dielectric characteristics under the same stress state.

• Proceedings of the KIEE Conference
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• 1991.11a
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• pp.293-295
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• 1991

In this study, we investigated the possibilty that $Pb(Mg_{1/3}Nb_{2/3})O_3-PbTiO_3-PbZrO_3$ ceramics with strontium substitutions could be used for piezoelectric sounders. Piezoelectric buzzer is one of them. By partially substituting Sr for Ph, dielectric constants had values greater than 2000, the value proper piezoelectric buzzer, piezoelectric constant($d_{31}$) had a maximum value, 298 $[10^{-12}C/N]$, at the Sr 5 mol % substitution. Sound level of piezoelectric buzzer had the highest value of 91 dB at the Sr 5 mol % substitution.

• Journal of the Korean Ceramic Society
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• v.12 no.2
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• pp.15-20
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• 1975

Ceramic resistors to be stable at high temperature were manufactured from using MgO, SiO2, SnO2, Bi2O3, and CeO2 by sintering in air at 125$0^{\circ}C$. Electrical resistivity with elevated temperatures was studied for the various system of the above oxides. The resistor, 1.0 MgO-1.0 SiO2-0.575 SnO2-0.005 Sb2O3-0.025 Bi2O3-0.013 CeO2 has the resistivity, (14.55$\pm$0.3)$\times$103 ohm in a temperature range from $25^{\circ}C$. to 80$0^{\circ}C$. It is concluded that the ceramics prepared by a dielectric compound and metal oxide semi-conductor has a good thermostability for electrical appliciations.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.8 no.2
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• pp.76-82
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• 2009

In this papers, Study on the Bonding property and Strength Evaluation in Bonding interface Joints of Dissimilar material using DOE. We found optimal condition that uses experimental design method (Response Surface Analysis, DOE) used temperature, pressure, time on experiment factor. And we could get bonding condition and strength that break and crack do not happen in mechanical processing about united dissimilar material. And progress 3 point bending tests and verified result.

• Proceedings of the KIEE Conference
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• 1997.07d
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• pp.1455-1458
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• 1997

In order to promote CO gas sensitivity, $SnO_2$ added ZnO prepared. The electrical conductivities and dielectric constants decreased by increasing $SnO_2$ content in air. The electrical conductivities in 1000ppm CO atmosphere were larger than in dry air. The measured CO sensitivities were $1{\sim}15.2$ at $100^{\circ}C{\sim}480^{\circ}C$. The maximum CO sensitivity of 15mol% $SnO_2$ added ZnO was 15.2 at $305^{\circ}C$.